Cleveland Clinic researchers have discovered a link between smoking’s impact on how myelodysplastic syndrome, or MDS, progresses in patients.

For the first time, specific genetic changes in MDS have been linked to a type of environmental exposure. The finding may someday pave the way for specific drugs that can target those molecular changes.

MDS, which usually appears in people over age 60, is a group of diseases in which the bone marrow doesn't make enough normal blood cells for the body. About 25 percent of cases are considered to be high risk for developing into leukemia. The only cure is a bone marrow transplant, although chemotherapy and some drug therapies are used to manage the condition.

In a study led by Dr. Mikkael Sekeres, a hematologist/oncologist at the Clinic’s Taussig Cancer Institute, researchers conducted gene sequencing (analyzing a person’s genetic makeup), and analyzed health records and smoking habits of 151 patients treated at the Clinic for MDS between 2000-2012.

The median age of the patients at diagnosis was 68, and the median survival was just over 3 ½ years. More than half of those patients – 54 percent – were current smokers or people who used to smoke, with a median tobacco exposure of more than 25 pack years (smoking one pack of cigarettes a day for 25 years).

The analysis revealed two things that weren’t unexpected – that the number of genetic abnormalities increases with age, and increases in line with how much someone smokes.

The cause of those abnormalities: an environmental pathogen found in cigarette smoke. That, in turn, impacted how well patients fared during treatment. Patients with MDS who smoke don’t live as long as non-smoking patients.

“Patients who smoke aren’t more likely to have [the disease] in advanced stages [at the time of diagnosis] than those who don’t smoke,” Sekeres said. “But because they smoke, they’re more likely to have other health conditions that make it harder to treat MDS.”

The difficulty comes in a patient’s inability to tolerate the treatment, or because the patient has other health conditions that have to be treated before the MDS.

Since the study’s initial publication in October in the journal Blood, the analysis has expanded to include more than 300 patients, with similar conclusions.

Sekeres said he would like to conduct more studies in patients who stop smoking following their diagnosis with MDS. “Do the genetic changes stop at that time, or are they still there?” he said.

“This class of genetic abnormalities is along a pathway that’s treatable,” Sekeres said. “That might mean using specific drugs for smokers to make the treatment more effective.”